Low force liquid metal interconnect solutions

ABSTRACT

Embodiments disclosed herein include an electronic package. In an embodiment, the electronic package comprises a package substrate having a first surface and a second surface opposite from the first surface, and a die on the first surface of the package substrate. In an embodiment, the electronic package further comprises a socket interface on the second surface of the package substrate. In an embodiment, the socket interface comprises a first layer, wherein the first layer comprises a plurality of wells, a liquid metal within the plurality of wells, and a second layer over the plurality of wells.

TECHNICAL FIELD

Embodiments of the present disclosure relate to semiconductor devices,and more particularly to interconnect architectures that utilize liquidmetal (LM) solutions.

BACKGROUND

As land grid array (LGA) packages continue to grow in size and number ofpads, the loading requirement for the socket to make them electricallyactive is also growing. This loading force impacts the first thermalinterface material (TIM1) performance and the shape of the integratedheat spreader (IHS) (which impacts the second TIM (TIM2) performance).

Liquid metal (LM) solutions have been proposed for providing socketinterconnects. However, LM solutions suffer from several criticallimitations. For example, even though the deposition processes for LMsare well described, there is little discussion on how to make stableelectrical connections considering LMs form an oxide shellinstantaneously. This prevents the LM from bonding to the electrical padon the CPU/substrate/PCB. It has been shown that strong acids and/orbases may be applied to the LM to break the oxide shell. However, suchtreatments may affect long term reliability. Additionally, suchtreatments have been shown to drive large resistance variations, whichis undesirable.

LMs are also hard to contain. For example, the LM tends to stick tosocket pins or can escape from the well. Furthermore, the films used tocontain the LM can become conductive, which results in an electricalshort. Reservoir based LM interconnect solutions involve more assemblysteps to form the reservoirs. They also introduce the risk ofcontaminating materials used in chip packaging since the LMs aretypically corrosive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional illustration of an electronic package witha socket interface that comprises liquid metal (LM) within wells overcontact pads, in accordance with an embodiment.

FIG. 1B is a cross-sectional illustration of an electronic package witha socket interface that comprises LM and a socket interfacing with thesocket interface, in accordance with an embodiment.

FIG. 2A is a cross-sectional illustration of a socket with LM for a pingrid array (PGA) electronic package, in accordance with an embodiment.

FIG. 2B is a cross-sectional illustration of a socket with LM and a PGAelectronic package attached to the socket, in accordance with anembodiment.

FIG. 3A is a cross-sectional illustration of a well with a LM thatcomprises a plurality of oxide shells around nanoparticles, inaccordance with an embodiment.

FIG. 3B is a cross-sectional illustration of a well with a coalesced LM,in accordance with an embodiment.

FIGS. 4A-4H are cross-sectional illustrations depicting a process forforming a socket interface with a coalesced LM, in accordance with anembodiment.

FIGS. 5A-5D are cross-sectional illustrations depicting a process forforming a coalescence socket used to coalesce a LM, in accordance withan embodiment.

FIG. 6 is a cross-sectional illustration of a socket pin attached to acontact pad with a LM, in accordance with an embodiment.

FIGS. 7A-7E are cross-sectional illustrations of a process for attachinga socket pin to a contact pad with a coalesced LM, in accordance with anembodiment.

FIG. 8 is a schematic of a computing device built in accordance with anembodiment.

EMBODIMENTS OF THE PRESENT DISCLOSURE

Described herein are interconnect architectures that utilize liquidmetal (LM) solutions, in accordance with various embodiments. In thefollowing description, various aspects of the illustrativeimplementations will be described using terms commonly employed by thoseskilled in the art to convey the substance of their work to othersskilled in the art. However, it will be apparent to those skilled in theart that the present invention may be practiced with only some of thedescribed aspects. For purposes of explanation, specific numbers,materials and configurations are set forth in order to provide athorough understanding of the illustrative implementations. However, itwill be apparent to one skilled in the art that the present inventionmay be practiced without the specific details. In other instances,well-known features are omitted or simplified in order not to obscurethe illustrative implementations.

Various operations will be described as multiple discrete operations, inturn, in a manner that is most helpful in understanding the presentinvention, however, the order of description should not be construed toimply that these operations are necessarily order dependent. Inparticular, these operations need not be performed in the order ofpresentation.

As noted above, liquid metal (LM) architectures have significant issueswhen used in socket interconnects. Accordingly, embodiments disclosedherein comprise socket designs that provide electrical activation of theLM. Particularly, the outer oxide shell of the LM is broken in order toallow for bonding to contact pad and the socket pin. The outer oxideshell is broken by a coalescence socket that stirs the LM. The stirringbreaks the oxide shell and allows for the LM to coalesce. Suchmechanical breaking of the oxide shell avoids the need for strong acidsor bases. Additionally, the mechanical coalescence of the LM allows forlow resistance variation (e.g., 2 mOhm or less).

Furthermore, since the LM provides an electrical connection between thesocket pin and the contact pad, there is no need to directly contact thesocket pin to the contact pad. This allows for lower forces to be usedduring socketing (e.g., less than 0.5 gram-force (gf)), even when theelectronic package exhibits significant warpage and for packages withlarge pin counts (e.g., 7,000 or greater, or 10,000 or greater).

Additionally, embodiments disclosed herein include a capping solutionthat prevents the LM from escaping from the well. For example, one ormore cap layers of a self-sealing material (e.g., a closed cell foam oran open cell foam) is used. The socket pin may be inserted through thecap layer, and the cap layer will provide a seal around the socket pin.Upon retraction of the socket pin, the cap layer will reseal and alsowill clean LM from the extracted socket pin. Furthermore, the cap layersdisclosed herein do not become electrically conductive. As such, thereis no risk of electrical shorts in the device. In an embodiment, such LMsocket architectures may be used for testing applications or for a finalproduct.

Referring now to FIG. 1A, a cross-sectional illustration of anelectronic package 100 is shown, in accordance with an embodiment. Theelectronic package may comprise a package substrate 101 and a die 102attached to the package substrate by interconnects 105. Theinterconnects 105 are shown as solder bumps. However, it is to beappreciated that any first level interconnect (FLI) may be used toconnect the die 102 to the package substrate 101. Additionally, while asingle die 102 is shown, it is to be appreciated that a plurality ofdies 102 may be included within the electronic package 100. In anembodiment, a heat spreader 103 may be thermally coupled to the die 102by a thermal interface material (TIM) 104.

In an embodiment, the package substrate 101 may comprise a plurality ofcontact pads 106. The contact pads 106 may be disposed along a surfaceof the package substrate 101 opposite from the die 102. In anembodiment, the one or more of the contact pads 106 may be electricallycoupled to the interconnects 105 through conductive routing (not shown)in the package substrate 101.

In an embodiment, a socket interface 110 may be disposed on theelectronic package 100. The socket interface 110 may be positioned overthe surface of the package substrate 101 opposite from the die 102. Inan embodiment, the socket interface 110 may comprise a first layer 112.The first layer 112 may comprise a plurality of wells 116. As such, thefirst layer 112 may be referred to herein as a “well layer” 112. In anembodiment, the well layer 112 may comprise a substantiallynon-conductive material, such as, but not limited to an organicpolymeric material (e.g., polyimide) or a patternable photoresist. Thewell layer 112 may be a laminated layer that is subsequently patterned.The wells 116 may each be aligned over one of the contact pads 106.

In an embodiment, a LM 113 is disposed in each of the wells 116. The LM113 may be any suitable LM 113 that is liquid at normal operatingtemperatures of the electronic package 100. In a particular embodiment,the LM 113 comprises gallium, or the LM 113 comprises a gallium basedalloy. Such LMs 113 have a very low melting point. Several eutecticcompositions of a gallium alloy stay in the liquid state at roomtemperature and below room temperature conditions. Unlike mercury,gallium alloys are safer, have low vapor pressures (i.e., they may notboil until approximately 1,500° C.) and are used in medical industries.

As noted above, a drawback to using LMs 113 is the formation of an oxideshell, which reduces the conductivity of the LM 113. Accordingly,embodiments may include a coalesced LM 113. That is, the LM 113 may besubstantially free of oxide shells. For example, a mechanicalcoalescence process may be used to coalesce the LM 113. Such amechanical process for coalescing the LM 113 is described in greaterdetail below.

While being benign to organic materials (such as the well layer 112),LMs 113 are known to react with most metals, resulting in damagingcorrosion. Accordingly, a second layer 115 is disposed over the welllayer 112. The second layer 115 may be referred to herein as a cappinglayer 115 since the capping layer 115 caps the wells 116. The cappinglayer 115 seals the well in order to prevent the LM 113 from escaping.

In an embodiment, the capping layer 115 is a self-sealing material. Forexample, the capping layer 115 may comprise a closed cell foam, an opencell foam, nonwoven or woven meshes, or an elastic material. The cappinglayer 115 may also comprise a composite of two or more differentmaterial layers. In an embodiment, the capping layer 115 may be alaminated layer or deposited with any other suitable deposition process.In an embodiment, the self-sealing property of the capping layer 115allows for a socket pin to be inserted through the capping layer inorder to contact the LM 113. After the pin breaks the seal, the cappinglayer 115 will seal against the pin. Upon removal of the pin, thecapping layer 115 will reseal itself. Additionally, the capping layer115 may be used to clean the pin during removal of the pin. That is, thecapping layer 115 may clean LM 113 off of the pin as the pin is removedfrom the well 116. In some embodiments, the capping layer 115 is alsopenetrateable with a low force. The capping layer 115 may also bechemically compatible with the LM 113 in order to prevent the cappinglayer 115 from becoming conductive and shorting the part.

Referring now to FIG. 1B, a cross-sectional illustration of anelectronic package 100 that is mated with a socket is shown, inaccordance with an embodiment. In an embodiment, the package 100 may besubstantially similar to the package 100 in FIG. 1A. As shown, socketpins 122 extending up from a socket substrate 121 penetrate the cappinglayer 115 and are inserted into the LM 113. Since the LM 113 iscoalesced, the LM provides an electrical path between the socket pins122 and the contact pads 106. Accordingly, the socket pins 122 do notneed to be in direct contact with the contact pads 106. This isparticularly beneficial when the package substrate 101 is warped. Assuch, the applied force during mating is reduced since warpage does notneed to be overcome. While all of the socket pins 122 are shown as beingspaced away from the contact pads 106, it is to be appreciated that dueto warpage, one or more of the socket pins 122 may contact pads 106.

Referring now to FIG. 2A, a cross-sectional illustration of a socket 230is shown, in accordance with an embodiment. In an embodiment, the socket230 may be used in conjunction with a package substrate that comprisesthe pins, such as a pin grid array (PGA) package. That is, the socket230 may not include pins in some embodiments.

In an embodiment, the socket 230 may comprise a socket substrate 221.The socket substrate 221 may be an organic substrate. The socketsubstrate 221 may comprise electrical routing (not shown). In someembodiments, the socket substrate 221 may be a board (e.g., a printedcircuit board (PCB)). A well layer 212 may be disposed over the socketsubstrate 221. The well layer 212 may comprise a plurality of wells 216.In an embodiment, the well layer 212 may comprise a substantiallynon-conductive material, such as, but not limited to an organicpolymeric material (e.g., polyimide) or a patternable photoresist. Thewell layer 212 may be substantially similar to the well layer 112described above.

In an embodiment, a LM 213 may be disposed in the wells 216. In anembodiment, the LM 213 may comprise gallium or a gallium alloy. The LM213 may be a coalesced LM 213. That is, the LM 213 may be substantiallyfree from oxide shells. The coalescing process may be implemented with amechanical coalescing process, as will be described in greater detailbelow. The LM 213 may be substantially similar to the LM 113 describedabove.

In an embodiment, a capping layer 215 is disposed over the well layer212. The capping layer 215 also covers the wells 216 in order to sealthe LM 213 within the wells 216. In an embodiment, the capping layer 215is a self-sealing material. For example, the capping layer 215 maycomprise a closed cell foam, an open cell foam, nonwoven or wovenmeshes, or an elastic material. The capping layer 215 may also comprisea composite of two or more different material layers. The capping layer215 may be substantially similar to the capping layer 115 describedabove.

Referring now to FIG. 2B, a cross-sectional illustration of anelectronic package 200 mated with the socket 230 is shown, in accordancewith an embodiment. The electronic package 200 may comprise a packagesubstrate 201 and a die 202 attached to the package substrate 201. Aheat spreader 203 may be thermally coupled to the die 202 by a TIM 204.In an embodiment, the electronic package 200 may comprise a plurality ofpins 222 that extend away from a surface of the package substrate 201opposite from the die 202. The pins 222 may be electrically coupled tothe die 202 through routing (not shown) in the package substrate 201. Inan embodiment, the electronic package 200 may be a PGA package.

As shown, the pins 222 are inserted through the capping layer 215 andinto the LM 213. In an embodiment, the LM 213 provides an electricalconnection between the pins 222 and conductive features (not shown) onthe surface of the socket substrate 221. That is, the pins 222 need notbottom out and directly contact the socket substrate 221 in order toform an electrical connection between the electronic package 200 and thesocket substrate 221.

Referring now to FIGS. 3A and 3B, cross-sectional illustrationsdepicting the difference between a LM 313′ as deposited and a coalescedLM 313 are shown, in accordance with an embodiment. In each of FIGS. 3Aand 3B, the LMs 313′ and 313 are deposited in a well of a well layer312. The well layer 312 is over a package substrate 301 and a contactpad 306. While shown in the context of a socket interface on anelectronic package, it is to be appreciated that substantially similarconcepts also apply when the LMs 313′ and 313 are on a socket substrate(e.g., similar to what is shown in FIGS. 2A and 2B).

Referring now to FIG. 3A, an as deposited LM 313′ is shown in the well.The LM 313′ is shown as comprising a plurality of nanoparticles. Theindividual nanoparticles may each comprise an oxide shell. The oxideshell may have a thickness of approximately 1 nm or less. Thenanoparticles of the LM 313′ may be generated through sonication ofliquid metal in a carrier solution. For example, the carrier solutionmay comprise isopropyl alcohol (IPA). The carrier solution drops thesurface tension of the LM 313′ and allows it to flow into the wells. Theoxide shells increase the electrical resistivity of the LM 313′ so thatthe LM 313′ is not suitable for providing an electrical interconnect.

In order to overcome the oxide shell and allow for improved electricalconductivity, a mechanical coalescence process is used. The coalesced LM313 is shown in FIG. 3B. As shown in the illustration, the nanoparticleshave coalesced into a single body of liquid (i.e., LM 313).Substantially removing the oxide shells results in a decrease in theelectrical resistivity and allows for the LM 313 to be used as anelectrical interconnect with a low resistance variation. For example,the resistance variation of the LM 313 in the various wells of anelectronic package may be less than approximately 5 mOhm, or less thanapproximately 2 mOhm.

Referring now to FIGS. 4A-4H, a series of cross-sectional illustrationsdepicting a process for forming a socket interface on an electronicpackage 400 is shown, in accordance with an embodiment.

Referring now to FIG. 4A, a cross-sectional illustration of anelectronic package 400 in a stage of manufacture is shown, in accordancewith an embodiment. The electronic package 400 comprises a packagesubstrate 401 with a plurality of contact pads 406. In an embodiment, awell layer 412 is disposed over the package substrate 401. The welllayer 412 may be disposed with a lamination process or the like. Thewell layer 412 may be substantially similar to the well layers 112, 212,312 described above. In an embodiment, the well layer 412 is patternedto form a plurality of wells 416. The wells 416 may be aligned with thecontact pads 406. For example, individual ones of the wells 416 may bedisposed over individual ones of the contact pads 406. As such, thecontact pads 406 may be exposed.

Referring now to FIG. 4B, a cross-sectional illustration of theelectronic package 400 after a LM 413′ is disposed into the wells 416 isshown, in accordance with an embodiment. In an embodiment, the LM 413′may comprise a plurality of nanoparticles with an oxide shell. Forexample, the LM 413′ may be similar in structure and composition to theLM 313′ described above with respect to FIG. 3A. In an embodiment, thenanoparticles of the LM 413′ may be generated through sonication ofliquid metal in an IPA carrier solution. The carrier solution drops thesurface tension of the LM 413′ and allows it to flow into the wells. Theoxide shells increase the electrical resistivity of the LM 413′ so thatthe LM 413′ is not suitable for providing an electrical interconnect.

Referring now to FIG. 4C, a cross-sectional illustration of theelectronic package 400 during the mechanical coalescing process isshown, in accordance with an embodiment. In an embodiment, a coalescingsocket 440 is inserted into the LM 413′. The coalescing socket 440comprises a socket body 441, a first layer 442 over the socket body 441,and a second layer 443 over the first layer 442. In an embodiment, asocket pin 444 extends through the first layer 442 and the socket body441. The second layer 443 presses down on the socket pin 444.

In an embodiment, the socket pin 444 extends down into the LM 413′. Inan embodiment, the socket pins 444 all extend down to the contact pads406. Even with warpage of the electronic package 400, this is madepossible by the construction of the coalescing socket 440. Particularly,the first layer 442 is a compressible layer. That is, the first layer442 can be locally compressed in order to provide non-uniformdisplacements of the socket pins 444 to accommodate the warpage. In someembodiments, the first layer 442 may be a foam.

It is to be appreciated that the coalescing socket 440 need not provideelectrical conductivity, since the socket is used to coalesce the LM413′ instead of for providing an electrical interconnect. As such, thesocket pins 444 may be any suitable material, including non-conductivematerials. For example, the socket pins 444 may be any rigid materialthat is metallic or non-metallic.

As shown by the arrows, the coalescing socket 440 is displaced back andforth so that the socket pins 444 pass through substantially the entirevolume of the well. This allows for the oxide shells of each of thenanoparticles of the LM 413′ to be broken and the LM 413′ to coalesce.While the arrows show displacement in the X-direction, it is to beappreciated that displacement may also be provided in the Y-direction(out of the plane of the page) and in the Z-direction, in order to breaksubstantially all of the oxide shells in the well.

The mechanical coalescence process is shown in greater detail in FIG.4D. As shown, the socket pin 444 is traversing from the left edge of thewell to the right edge of the well. The LM 413 to the left of the socketpin 444 has been coalesced, whereas the LM 413′ to the right of thesocket pin 444 remains uncoalesced with oxide shells aroundnanoparticles. As the socket pin 444 continues to traverse to the rightedge of the well, all of the remaining LM 413′ will also be converted tocoalesced LM 413.

Referring now to FIG. 4E, a cross-sectional illustration of theelectronic package 400 after all of the LM 413′ has been coalesced intoLM 413 is shown, in accordance with an embodiment. At this point, the LM413 is electrically active and bonded to the underlying contact pads406. The LM 413 can now be used to provide an electrical interconnect toan electrical socket pin.

Referring now to FIG. 4F, a cross-sectional illustration of theelectronic package 400 after a capping layer 415 is disposed over thewell layer 412 is shown, in accordance with an embodiment. In anembodiment, the capping layer 415 is a self-sealing layer. For example,the capping layer 415 may comprise a closed cell foam, an open cellfoam, nonwoven or woven meshes, or an elastic material. The cappinglayer 415 may also comprise a composite of two or more differentmaterial layers. In an embodiment, the capping layer 415 may be alaminated layer or deposited with any other suitable deposition process.In an embodiment, the self-sealing property of the capping layer 415allows for a socket pin to be inserted through the capping layer inorder to contact the LM 413. After the pin breaks the seal, the cappinglayer 415 will seal against the pin. Upon removal of the pin, thecapping layer 415 will reseal itself. Additionally, the capping layer415 may be used to clean the pin during removal of the pin. That is, thecapping layer 415 may clean LM 413 off of the pin as the pin is removedfrom the well 416. In some embodiments, the capping layer 415 is alsopenetrateable with a low force. The capping layer 415 may also bechemically compatible with the LM 413 in order to prevent the cappinglayer 415 from becoming conductive and shorting the part.

In some embodiments, the processing may end after the formation of thecapping layer 415. However, in other embodiments, additional structuresmay be included in the socket interface. For example, in FIG. 4G, asecond well layer 417 is disposed over the capping layer 415. The secondwell layer 417 may have wells 418 that are aligned over the LM 413.

Referring now to FIG. 4H, a cross-sectional illustration of theelectronic package 400 after a second capping layer 419 is disposed overthe second well layer 417 is shown, in accordance with an embodiment.The inclusion of the second well layer 417 and the second capping layer419 provide a second confined well 418 in order to provide furtherprotection against the LM 413 spreading about the electronic package400. In an embodiment, the capping layer 415 and the second cappinglayer 419 may comprise the same material. In other embodiments, thecapping layer 415 and the second capping layer 419 comprise differentmaterials.

In FIGS. 4A-4H, the socket interface is shown as being formed on anelectronic package. However, it is to be appreciated that the socketinterface may be formed on a board (e.g., a PCB) or on any other type ofsubstrate used for interfacing with a socket pin architecture.

Referring now to FIGS. 5A-5D, a series of cross-sectional illustrationsdepicting a process for forming a coalescence socket 540 is shown, inaccordance with an embodiment.

Referring now to FIG. 5A, a cross-sectional illustration of a socketbody 541 of a socket 540 is shown, in accordance with an embodiment. Inan embodiment, the socket body 541 may comprise a plurality of holes 545that pass through the socket body.

Referring now to FIG. 5B, a cross-sectional illustration of the socket540 after a first layer 542 is disposed over the socket body 541 isshown, in accordance with an embodiment. The first layer 542 may be aneasily compressible material or spring material. For example, the firstlayer 542 may be a foam or the like. In an embodiment, the holes 545 mayalso pass through the first layer 542.

Referring now to FIG. 5C, a cross-sectional illustration of the socket540 after socket pins 544 are disposed through the holes 545 is shown,in accordance with an embodiment. In an embodiment, the socket pins 544comprise a pin 547 and a head 546. The pin 547 passes through the holes545 and the head 546 rests on the first layer 542. The socket pins 544may be a metallic material or a non-metallic material.

Referring now to FIG. 5D, a cross-sectional illustration of the socket540 after a second layer 543 is disposed over the socket pins 544 isshown, in accordance with an embodiment. In an embodiment, the secondlayer 543 compresses the head 546 against the first layer 542. Thepresence of the first layer 542 allows for non-uniform displacement ofthe pins 547 in order to account for warpage in an underlying substrate,as described above.

In the embodiments described above, the LM materials are disclosed asbeing confined in a well. However, it is to be appreciated thatembodiments are not limited to such configurations. This is because theoxide shells of uncoalesced LMs are sticky. Therefore, the uncoalescedLMs may be attached to a socket pin with a dipping process. A mechanicalcoalescing process may then be implemented to convert the uncoalesced LMinto an electrically active coalesced LM.

Referring now to FIG. 6 , a cross-sectional illustration of anelectronic package 600 is shown, in accordance with an embodiment. Theelectronic package 600 comprises a package substrate 601 with a contactpad 606. In an embodiment, a socket pin 622 is electrically coupled tothe contact pad 606 by a coalesced LM 613. The coalescing of the LM 613provides a mechanical bond between the contact pad 606 and the LM 613,and a mechanical bond between the socket pin 622 and the LM 613.Additionally, the LM 613 may wet up a sidewall surface of the socket pin622 and along the surface of the contact pad 606. As such, the LM 613may have a characteristic fillet shape.

Referring now to FIGS. 7A-7E, a series of cross-sectional illustrationsdepicting a process for attaching a socket pin to a contact pad with aLM is shown, in accordance with an embodiment.

Referring now to FIG. 7A, a cross-sectional illustration of socket pins722 attached to a socket substrate 755 is shown, in accordance with anembodiment. As shown, the socket pins 722 are dipped into a bath 750 ofa LM 713′. In an embodiment, the LM 713′ is an uncoalesced LM 713′. Thatis, the LM 713′ comprises nanoparticles with oxide shells. In anembodiment, the socket pins 722 are dipped into a bath 750 thatcomprises LM 713′ before the LM 713′ is sonicated or after the LM 713′is sonicated.

Referring now to FIG. 7B, a cross-sectional illustration of the socketpins 722 after they are extracted from the bath 750 is shown, inaccordance with an embodiment. As shown, portions of LM 713′ remainsattached to the socket pins 722. This is because the oxide shells aretacky, and tend to stick to many different materials, including thesocket pins 722.

Referring now to FIG. 7C, a cross-sectional illustration of the socketpins 722 being brought into contact with contact pads 706 on a substrate701 is shown, in accordance with an embodiment. As shown by the arrows,a downward pressure is applied to the socket substrate 755 and thesocket substrate is displaced laterally back and forth. This pressureand lateral displacement mechanically breaks the oxide shell and allowsthe LM 713′ to coalesce.

Referring now to FIG. 7D, a cross-sectional illustration of the socketpins 722 attached to the contact pads 706 is shown, in accordance withan embodiment. In an embodiment, the LM 713 is now coalesced and bondedto the socket pins 722 and the contact pads 706. As shown, the LM 713,may form a characteristic fillet shape, as described above.

Referring now to FIG. 7E, a cross-sectional illustration of the socketpins 722 after a clamping force is applied between the socket substrate755 and the substrate 701 is shown, in accordance with an embodiment. Aclamping force may be needed in order to secure the socket pins 722 tothe contact pads 706. For example, a screw or clamp 757 may span betweenthe socket substrate 755 and the substrate 701.

FIG. 8 illustrates a computing device 800 in accordance with oneimplementation of the invention. The computing device 800 houses a board802. The board 802 may include a number of components, including but notlimited to a processor 804 and at least one communication chip 806. Theprocessor 804 is physically and electrically coupled to the board 802.In some implementations the at least one communication chip 806 is alsophysically and electrically coupled to the board 802. In furtherimplementations, the communication chip 806 is part of the processor804.

These other components include, but are not limited to, volatile memory(e.g., DRAM), non-volatile memory (e.g., ROM), flash memory, a graphicsprocessor, a digital signal processor, a crypto processor, a chipset, anantenna, a display, a touchscreen display, a touchscreen controller, abattery, an audio codec, a video codec, a power amplifier, a globalpositioning system (GPS) device, a compass, an accelerometer, agyroscope, a speaker, a camera, and a mass storage device (such as harddisk drive, compact disk (CD), digital versatile disk (DVD), and soforth).

The communication chip 806 enables wireless communications for thetransfer of data to and from the computing device 800. The term“wireless” and its derivatives may be used to describe circuits,devices, systems, methods, techniques, communications channels, etc.,that may communicate data through the use of modulated electromagneticradiation through a non-solid medium. The term does not imply that theassociated devices do not contain any wires, although in someembodiments they might not. The communication chip 806 may implement anyof a number of wireless standards or protocols, including but notlimited to Wi-Fi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE,GSM, GPRS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well asany other wireless protocols that are designated as 3G, 4G, 5G, andbeyond. The computing device 800 may include a plurality ofcommunication chips 806. For instance, a first communication chip 806may be dedicated to shorter range wireless communications such as Wi-Fiand Bluetooth and a second communication chip 806 may be dedicated tolonger range wireless communications such as GPS, EDGE, GPRS, CDMA,WiMAX, LTE, Ev-DO, and others.

The processor 804 of the computing device 800 includes an integratedcircuit die packaged within the processor 804. In some implementationsof the invention, the integrated circuit die of the processor may bepart of an electronic package that is electrically coupled to a boardwith a LM socket interface, in accordance with embodiments describedherein. The term “processor” may refer to any device or portion of adevice that processes electronic data from registers and/or memory totransform that electronic data into other electronic data that may bestored in registers and/or memory.

The communication chip 806 also includes an integrated circuit diepackaged within the communication chip 806. In accordance with anotherimplementation of the invention, the integrated circuit die of thecommunication chip may be part of an electronic package that iselectrically coupled to a board with a LM socket interface, inaccordance with embodiments described herein.

The above description of illustrated implementations of the invention,including what is described in the Abstract, is not intended to beexhaustive or to limit the invention to the precise forms disclosed.While specific implementations of, and examples for, the invention aredescribed herein for illustrative purposes, various equivalentmodifications are possible within the scope of the invention, as thoseskilled in the relevant art will recognize.

These modifications may be made to the invention in light of the abovedetailed description. The terms used in the following claims should notbe construed to limit the invention to the specific implementationsdisclosed in the specification and the claims. Rather, the scope of theinvention is to be determined entirely by the following claims, whichare to be construed in accordance with established doctrines of claiminterpretation.

Example 1: an electronic package, comprising: a package substrate havinga first surface and a second surface opposite from the first surface; adie on the first surface of the package substrate; and a socketinterface on the second surface of the package substrate, wherein thesocket interface comprises: a first layer, wherein the first layercomprises a plurality of wells; a liquid metal within the plurality ofwells; and a second layer over the plurality of wells.

Example 2: the electronic package of Example 1, wherein the packagesubstrate comprises a plurality of pads on the second surface, whereinindividual ones of the plurality of pads are aligned with individualones of the plurality of wells.

Example 3: the electronic package of Example 1 or Example 2, wherein thesecond layer confines the liquid metal to the plurality of wells.

Example 4: the electronic package of Examples 1-3, wherein the secondlayer comprises a self-sealing material.

Example 5: the electronic package of Examples 1-4, wherein the secondlayer comprises one or more of a closed cell foam, an open cell foam, anonwoven mesh, a woven mesh, or an elastic material.

Example 6: the electronic package of Example 5, wherein the second layeris a laminated stack.

Example 7: the electronic package of Example 5, wherein the second layeris a composite material.

Example 8: the electronic package of Examples 1-7, wherein the pluralityof wells comprises approximately 7,000 or more wells.

Example 9: the electronic package of Examples 1-8, further comprising: asocket attached to the package substrate, wherein the socket comprises:a socket substrate; and a plurality of pins extending away from thesocket substrate, wherein individual ones of the plurality of pins areinserted into individual ones of the plurality of wells.

Example 10: the electronic package of Example 9, wherein the pluralityof pins are electrically coupled to the package substrate by the liquidmetal.

Example 11: the electronic package of Examples 1-10, wherein the liquidmetal comprises gallium or a gallium based alloy.

Example 12: the electronic package of Example 11, wherein the liquidmetal in the plurality of wells is coalesced.

Example 13: a socket for providing electrical interconnects to anelectronic package, comprising: a substrate; a first layer over thesubstrate, wherein the first layer comprises a plurality of wells; aliquid metal in the plurality of wells; and a second layer over thefirst layer, wherein the second layer confines the liquid metal to theplurality of wells.

Example 14: the socket of Example 13, wherein the electronic package isa pin grid array (PGA) package, and wherein a plurality of pins of thePGA package are aligned with the plurality of wells.

Example 15: the socket of Example 13 or Example 14, wherein the secondlayer comprises a self-sealing material.

Example 16: the socket of Example 15, wherein the second layer comprisesone or more of a closed cell foam, an open cell foam, a nonwoven mesh, awoven mesh, or an elastic material.

Example 17: the socket of Examples 13-16, wherein the liquid metalcomprises gallium or a gallium based alloy.

Example 18: the socket of Example 17, wherein the liquid metal in thewells is coalesced.

Example 19: the socket of Examples 13-18, wherein the plurality of wellscomprises approximately 7,000 or more wells.

Example 20: a socket, comprising: a socket body; a first layer over thesocket body, wherein a plurality of openings pass through the firstlayer and the socket body; a plurality of pins passing through theplurality of openings, wherein individual ones of the plurality of pinscomprise a head with a width greater than a width of individual ones ofthe openings; and a second layer over the first layer, wherein thesecond layer presses the heads of the plurality of pins against thefirst layer.

Example 21: the socket of Example 20, wherein the first layer iscompressible.

Example 22: the socket of Example 21, wherein the first layer is a foam.

Example 23: the socket of Examples 20-22, wherein the plurality of pinsare non-conductive.

Example 24: an electronic system, comprising: a board; and an electronicpackage electrically coupled to the board by a socket, wherein thesocket comprises: a first layer, wherein the first layer comprises aplurality of wells; a liquid metal within the plurality of wells; and asecond layer over the plurality of wells.

Example 25: the electronic system of Example 24, wherein the liquidmetal comprises a coalesced gallium or a gallium based alloy.

What is claimed is:
 1. An electronic package, comprising: a packagesubstrate having a first surface and a second surface opposite from thefirst surface; a die on the first surface of the package substrate; anda socket interface on the second surface of the package substrate,wherein the socket interface comprises: a first layer, wherein the firstlayer comprises a plurality of wells; a liquid metal within theplurality of wells; and a second layer over the plurality of wells,wherein the second layer is vertically overlapping with the liquidmetal, and wherein the second layer is continuous between adjacent onesof the plurality of wells.
 2. The electronic package of claim 1, whereinthe package substrate comprises a plurality of pads on the secondsurface, wherein individual ones of the plurality of pads are alignedwith individual ones of the plurality of wells.
 3. The electronicpackage of claim 1, wherein the second layer confines the liquid metalto the plurality of wells.
 4. The electronic package of claim 1, whereinthe second layer comprises a self-sealing material.
 5. The electronicpackage of claim 1, wherein the second layer comprises one or more of aclosed cell foam, an open cell foam, a nonwoven mesh, a woven mesh, oran elastic material.
 6. The electronic package of claim 5, wherein thesecond layer is a laminated stack.
 7. The electronic package of claim 5,wherein the second layer is a composite material.
 8. The electronicpackage of claim 1, wherein the plurality of wells comprisesapproximately 7,000 or more wells.
 9. The electronic package of claim 1,further comprising: a socket attached to the package substrate, whereinthe socket comprises: a socket substrate; and a plurality of pinsextending away from the socket substrate, wherein individual ones of theplurality of pins are inserted into individual ones of the plurality ofwells.
 10. The electronic package of claim 9, wherein the plurality ofpins are electrically coupled to the package substrate by the liquidmetal.
 11. The electronic package of claim 1, wherein the liquid metalcomprises gallium or a gallium based alloy.
 12. The electronic packageof claim 11, wherein the liquid metal in the plurality of wells iscoalesced.
 13. A socket for providing electrical interconnects to anelectronic package, comprising: a substrate; a first layer over thesubstrate, wherein the first layer comprises a plurality of wells; aliquid metal in the plurality of wells; and a second layer over thefirst layer, wherein the second layer confines the liquid metal to theplurality of wells, wherein the second layer is vertically overlappingwith the liquid metal, and wherein the second layer is continuousbetween adjacent ones of the plurality of wells.
 14. The socket of claim13, wherein the electronic package is a pin grid array (PGA) package,and wherein a plurality of pins of the PGA package are aligned with theplurality of wells.
 15. The socket of claim 13, wherein the second layercomprises a self-sealing material.
 16. The socket of claim 15, whereinthe second layer comprises one or more of a closed cell foam, an opencell foam, a nonwoven mesh, a woven mesh, or an elastic material. 17.The socket of claim 13, wherein the liquid metal comprises gallium or agallium based alloy.
 18. The socket of claim 17, wherein the liquidmetal in the wells is coalesced.
 19. The socket of claim 13, wherein theplurality of wells comprises approximately 7,000 or more wells.
 20. Anelectronic system, comprising: a board; and an electronic packageelectrically coupled to the board by a socket, wherein the socketcomprises: a first layer, wherein the first layer comprises a pluralityof wells; a liquid metal within the plurality of wells; and a secondlayer over the plurality of wells, wherein the second layer isvertically overlapping with the liquid metal, and wherein the secondlayer is continuous between adjacent ones of the plurality of wells. 21.The electronic system of claim 20, wherein the liquid metal comprises acoalesced gallium or a gallium based alloy.